Educational familiarization only. This original TechOpsBase resource explains system purpose, architecture and maintenance reasoning. It does not reproduce Airbus pages, diagrams, procedures, limits or controlled maintenance data. Actual aircraft work requires current approved data, correct effectivity, operator procedures, authorization, safety precautions and supervision.
Resource profile
- Aircraft: Airbus A350 family
- ATA chapter: 32 — Landing Gear
- Audience: Students, junior technicians and working professionals
- Level: Intermediate familiarization
- Source basis: Privately supplied legacy manufacturer training and MSG-3 material
- Technical status: Draft pending technical review
Learning objectives
- Trace a normal gear sequence.
- Explain management-system interlocks.
- Identify lock and door confirmation points.
- Differentiate movement and indication faults.
- Use a sequence-based troubleshooting method.
1. Command validation
The landing-gear lever is a request to the management system, not a direct hydraulic valve. The system considers aircraft state, available power, control-channel health and sequence prerequisites before commanding movement.
This architecture prevents unsafe or contradictory actions and allows monitoring throughout the sequence. A failed prerequisite can stop movement even when the lever and actuator are serviceable.
2. Door and gear sequence
The typical functional order is: validate command, release/open doors, release the gear lock, move the gear, engage the destination lock, confirm position, and command the required final door state. The exact sequence depends on extension or retraction and configuration.
Troubleshooting should identify the last confirmed correct step. That immediately narrows the likely fault region to the next command, power path, mechanical action or feedback signal.
3. Monitoring and indication
Discrete position sensors report gear, lock and door states. The management system compares commanded and actual states and presents normal, transit or unsafe information. Maintenance reports add channel and component context.
A disagreement does not prove the gear is mechanically unsafe, and a normal indication does not replace physical safing. Use approved inspection and test methods to resolve the difference.
4. Fault-isolation model
Classify the fault as command, electrical supply, hydraulic supply, valve/actuator, mechanical lock or obstruction, or sensor/data. Compare all three gears and both sides because common-source and local faults produce different patterns.
Avoid repeated cycling without understanding the hazard. Cycling can worsen a mechanical obstruction, consume stored energy or place personnel in danger.
Maintenance boundary
This lesson supports system understanding and maintenance reasoning. It deliberately excludes task steps, numerical limits, servicing quantities, torque values, dispatch decisions and configuration-specific instructions. Before touching the aircraft, confirm the current approved maintenance data, aircraft effectivity, safety procedures, tooling, personnel authorization and restoration requirements.
Review prompts
- What is the commanded function?
- Which computer or control channel accepts the command?
- Which energy source performs the movement or braking action?
- Which mechanical locks, valves or actuators must change state?
- Which sensors confirm that the commanded state was achieved?
- What independent or alternate path remains available?
- What hazards exist if maintenance personnel assume the indication alone proves the system is safe?
